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2.6 Fuel and lubricant oil
Rotax 912 UL and 912 ULS engines use many approved fuel types. Details are enclosed in
the engine maintenance manual. In our conditions we recommend using the Natural 95
gasoline. Peruse the demands for the fuel prescribed by the producer in detail. If the situation
demands it’s good to know what other fuel types are possible to use.
There are also conditions prescribed by the producer for the oil used in the engine. These
conditions are also enclosed in the engine maintenance manual. In our conditions we
recommend the oil Castrol GTX 3. There are types of oil which can shorten the oil and oil
filter change period from 100 to 50 flight hours. These details are included in the engine
maintenance manual.
2.6.1 Fuel supply
Volume of tank
Unusable amount of fuel
Minimum amount of fuel for take off
68 liters
3 liters
8 liters
Unusable amount of fuel is such amount of fuel in the tank at which the first symptoms of the
lack of the fuel can occur at normal conditions.
2.6.2 Consumption of fuel
The consumption of fuel depends on the type of used propeller, engine, flying technique, total
weight of the airplane, flight altitude, flight regime and the consumption is also influenced by
the meteorological conditions (consumption increases with higher temperatures). In general,
flight with heavier airplane requires higher engine output.
Aerodynamic drag increases with the speed of the flight and that’s why the consumption of
the fuel increases with higher speed. The consumption - output curve of the engine is
enclosed in the engine maintenance manual. Used propeller influences the consumption as
well. Adjustable propeller can be a compromise among various flight regimes. By using an
adjustable propeller consumption can decrease by 10-15%.
By using the fuel computer, which shows immediate consumption of the fuel, you can
optimize flight regime and achieve another reduction in the consumption.
2.7 Crew
2.7.1 Minimum and maximum weight of the crew
FM-250 Vampire
has two seats and there are three restrictions considering the weight limits.
First is the minimum weight of the crew, which is 70 kg. This minimum weight ensures that
the center of gravity is kept in the limits and so the good controllability and the stability of the
flight are preserved. If this condition is not fulfilled it is necessary to fasten respective amount
of weight to the other seat.
Second restriction is not to exceed
the maximum take off weight of the airplane, which is
450kg.
Third restriction is the maximum load of one seat, which is not more than 100 kg.
Flight Manual Page 14 of 40
